Heart arrhythmia are usually caused by improper or abnormal coordination of electrical impulses in a patient's heart. They can present themselves as a fast, slow, or irregular heart beat. Electrophysiology (EP) procedures or studies, such as radio frequency ablation (RFA), are conducted by cardiac medical specialists to help diagnose and treat these abnormal heart rhythms of patients. This is generally described in an article by M. Haissaguerre, L. Gencel, B. Fischer, P. Le Metayer, F. Poquet, F. I. Marcus, and J. Clementy, entitled “Successful Catheter Ablation of Atrial Fibrillation,” J. Cardiovasc Electrophysiol, 1994, pp. 1045-1052, Vol. 5.
At the beginning of an EP procedure, a catheter is inserted into a blood vessel near the groin of a patient and guided to the heart. The specialist will use specialized EP procedure tools to then conduct heart rhythm tests and, if warranted, treatment. Specifically, RFA is a treatment that heats the heart tissue to the point of causing lesions that will block certain electrical pathways in the heart tissue that are contributing to an arrhythmia. Ablation treatment decisions by the specialist can either be based on electrical signals (e.g., flutter, AVNRT) or on anatomy, respectively. In particular, treatment of atrial fibrillation (Afib) is based on anatomy, because specific sections of the pulmonary veins are primary ablation targets. Ablation treatment itself may be carried out using an irrigated ablation catheter.
Such ablation and other EP procedures are routinely conducted under image guidance, for example, using mono-plane and bi-plane X-ray fluoroscopy, to provide visualization and localization of both a patient's anatomy and the respective EP procedure tools. In the case of RFA, this allows the specialist to target ablation points within the heart. Ablations lesions are usually set by applying radio-frequency energy to endocardial tissue or even epicardial heart tissue. Recently, an augmented fluoroscopy system has been developed that is capable of overlaying image information involving the heart and targeted ablation locations from pre-operative image data for additional guidance. The system specifically is capable of fusing properly rendered 3D anatomical heart information, as well as planned ablation locations, with 2D fluoroscopy projections for enhanced guidance during EP procedures. This is detailed in a first article by F. Bourier, F. Heisenhuber, H J. Schneider, P. Ganslmeier, R. Fischer, A. Brost, M. Koch, N. Strobel, J. Hornegger, and K. Kurzidim, entitled “3D-Funktionalitat und Navigation durch einen Siemens-Prototypen in der biplanen Fluoroskopie zur Pulmonalvenenisolation,” Deutsche Gesellschaft fur Kordiologie, Jahrestagung, 2011, Mannheim, and a second article by F. Bourier, H J. Schneider, P. Ganslmeier, F. Heisenhuber, R. Fischer, A. Brost, M. Koch, N. Strobel, J. Hornegger, and K. Kurzidim, entitled “Unterstuetzung der transseptalen Punktion durch vorherige Oberlagerung eines 3D-Volumens von linkem Atrium und Aorta,” Deutsche Gesellschaft fur Kordiologie, Jahrestagung, 2011, Mannheim, each of which is incorporated by reference herein. The 3D data may involve pre-operative magnetic resonance images (MRI) or computed tomography (CT) images of a patient's heart.
A pre-operative 3D magnetic resonance (MR) or computed tomography (CT), or C-arm computed tomography (CACT), image of the patient's chest can offer important insights into a patient's heart anatomy. This pre-operative data can be used to provide additional information during the respective EP procedure by overlaying 2D perceptive renderings of the 3D data upon the intra-operative fluoroscopic images. However, although useful, such overlay image information offers only approximate guidance because of intra-operative heart beating motions, breathing motions, and catheter motions. It would be advantageous to dynamically update the overlay image information in order to account for these motions.